Evaluation of the efficacy of electrochemically activated solutions against nosocomial pathogens and bacterial endospores

Aims: Electrochemically activated solutions (ECAS) are generated from halide salt solutions via specially designed electrolytic cells. The active solutions are known to possess high biocidal activity against a wide range of target microbial species, however, literature revealing the kill-kinetics of these solutions is limited. The aim of the study was to identify the kill-rate and extent of population kill for a range of target species (including endospores) using ECAS generated at the anode (anolyte). Methods and Results: Standard suspensions of methicillin-resistant Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus atrophaeus spores and Clostridium difficile spores were treated with anolyte in a quantitative suspension assay. For vegetative cells, all concentrations of anolyte tested reduced the viable population to below the detection limit within 10 s. At a concentration of 99%, anolyte produced a log(10) reduction factor of greater than five in viable B. atrophaeus endospores within 90 s and reduced numbers of C. difficile endospores to below the experimental detection limit within 20 s at concentrations of 5% or greater. Conclusions: Anolyte was highly effective in killing test-bacteria and spores. The bactericidal efficacy was retained against vegetative cells at dilutions as low as 1% and against C. difficile spores as low as 5%. Significance and Impact of Study: The results of this study demonstrate that ECAS are effective at lower concentrations and act more rapidly than previously reported. Potent bactericidal and sporicidal activity coupled with point-of-use generation, low production-costs and environmental compatibility suggest that acidic ECAS has the potential to be a useful addition to the current armoury of disinfectants.